Imber, probably the city's leading modern tour guide, gives twice-daily van tours of Palm Springs modern architecture, often selling out well in advance. An enthusiastic raconteur, Imber takes folks past hundreds of buildings, from landmarks to obscurities. "This is my livelihood," he says, "and this is my passion." For a time he even gave tours leading people on Segway scooters.

In cities throughout the United States, realtors specializing in modern homes arranged tours to spur homebuyer appreciation. And architects, hoping to find clients, got into the act as well, often working through their local chapter of the American Institute of Architects to show off their modern-home projects.

"Our goal is to promote local architects, meaning members of our chapter," says architect Steve Stept, who has overseen home tours for the East Bay chapter of the AIA. The focus includes "how architects can work with you," he adds.

In Houston, Texas, as part of Modern Home Tours' two-dozen home tours in 2012, tour goers check in at showtime.

Many home tours raise funds for worthy causes. In Marin County, the 'Open Hearts, Open Homes' tours of Eichlers have benefited Hospice by the Bay, a pioneering program that helps the terminally ill and their families. And in Palo Alto, another Eichler tour has benefited Habitat for Humanity.

For-profit players

And now there is a new type of player—someone interested in building community, sure; and in preserving architecture, of course; and in promoting the work of practicing architects, naturally; and even in helping realtors, why not?

But this new player has got something else foremost in mind—making a profit.

At least two for-profit companies are running modern home tours—Dwell magazine, which runs tours as part of its larger publication business, and a new company that focuses entirely on modern home tours—Modern Home Tours, LLC.

In 2012, the four-year-old company, based in Austin, staged 26 modern tours in such varied locales as Chicago, Cincinnati, Boulder, Kansas City, Los Angeles, Silicon Valley, and the East Bay.

Tour organizer Gretchen Steinberg of SacMod.

The success of some of these tours surprised even Modern Home Tours' founder and co-owner Matt Swinney. "For a first-time city, Dallas, it was shocking to me. Dallas is not considered a modern market at all. We had 1,200 people on the first tour."

Why are modern tours popular enough to attract folks willing to pony up $40 or more to see someone else's home? Who are these someone else's who will let complete strangers tromp through their bedrooms and baths? Are these tours lighthearted expeditions—or something more serious?

Folks who attend, organize, benefit from, and donate their homes to modern tours run the gamut, from architects who see them as a way to spread word about their work to "looky-loos," Steinberg says. "People love seeing how other people live."

Linda Siguenza, who has spearheaded two tours of Eichler homes in the San Mateo Highlands, cites three benefits of the events: raising money to help local schools, boosting real estate values, and "bringing the community together."

Modern home tours provide other benefits as well—depending on their goals and exactly what type of tour they are.

Many modern tours focus on older homes, some on homes that are brand new, others on both. Either may bring in architects, contractors, furniture designers, artists, or interior designers to show off and talk about their services or wares.